Frequency changer



Sept. 13, 1932. L, LEVY 1,877,409

Y FREQUENCY CHANGER Filed May 24. 1928 Zaal-er! ldey b] S www@ Patented Sept. 13, 1932 UNITED STATES LUGIEN LEvY, oE 'rEIsQ EEANCE EEEQUENcY CHANGER.

Application mea nay 24, 192s, serial No. 280,354,211 in Evalue may ao, 1927.

It is known that electric oscillations may be produced by means of a vacuum tube the grid and plate circuits of which are suitably coupled and have proper electric characteristics. The oscillations are maintained by the variations of the resistance of the space between the plate and the filament under the influence of the varying potential of the grid with reference to the filament.4

These variations of resistance are in proper phase when the alternating voltage between the filament and the grid is in phase opposition with that between the plate and the filament.

It is also known that chiefly in the neutrodyne devices, the reaction due tothe alternating voltage appearing in the impedance of the plate circuit may be compensated by setting up in the grid circuit a voltage having a phase in opposition to that in the plate circuit.

It is therefore necessary in a great number of cases to provide in the plate and grid circuits of the usual vacuum tubes, voltages almost exactly in phase opposition. This result is diiiicult to obtain and requires delicate adjustments, complicated connections and causes unavoidably an increased expense of energy. Moreover a mere variation in the phase of the voltage between the grid and the lament causes thev oscillating state of the generating tubes to vary suddenly whereby the said tubes are submitted to mechanical stresses and may break.

-My invention has for its object electron discharge tubes and connections devised therefor which remove the drawbacks disclosed hereinabove. It consists in controlling the modications in the resistance of the space between the plate and the ilament no more by means of a grid disposed between the said plate and `filament but through an auxiliary conductor disposed on the side of the filament opposed to the plate whereby the variations in the potential of this conductor cause variations in the plate current which are opposed to those which would arise through the same variations in the potential of a grid disposed between the la- 50 ment and the plate. l

'creases whenV the control conductor In other words, the plate' current decreases When the controlling conductor is brought to positive increasing voltages with'reference to the filament whereas the plate current in- 1s brought to negative increasing voltages. This is due to thefact that, owing to the relative position of the electrodes, the electrons near thefilament move away from the cfntrol conductor as they move towards the Vp ate. n

It is obvious that such an electron discharge Vtube allows the oscillations to. be

maintained, the voltages to be amplified," the successive amplications to be neutrodyned,

etc. I obtain this result by means-of con- -nections which also form part of the inven- ,manner directly with the plate.

V'I`heicontrol conductor may be connected I with theV filament through resistances or choking coils andf in its connection with the platea condenser may be inserted if it is necessary Vto avoid this control conductor from being given the constant potential applied to the plate.. A

I have described hereinbelow by way of example with reference to the accompanying drawinga form ofexecution of my invention.

`The figure is a wiring diagram wherein .the tube according to the `invention acts as a frequency changer. This ligure shows a .tube with a grid built according tothe invention and adapted to serve in an autodyne .receiver which may `be used as `affrequency changer"y according to the. superheterodyne method. i y f i The anode andthe-control conductor may be constituted by platesparallel to the filament.j" l

The control conductor 6 might be given a great variety of shapes, such as that of a grid or plate. It might also appear as a plurality of grids on the side of the lament op osed tothe plate.

ue to the fall of potential in the circuit 11, E the point4 12 and consequently the controlling conductor 6 will be at a potential below that ofthe filament 2. Therefore the conductor 6 will repel the electrons and have a tendency to increase'the plate current. As this current increases the fall of potential across the circuit 11 will also increase and thereby the difference of potential between the filament and the conductor 6 and the repulsiyeaction of the conductor 6 will become greater.l

The control conductor has thus the effect of increasing the variations' of the-'plate' cur-1 rent so that the oscillations are excited and reach rapidly a steady regimen.

The wireless waves are receivedrby the aerial 18 consisting for instanceina' frame shunted by an adjustable condenser 7 and inserted between the filament 2 and the grid 10. lIt is tuned tothe frequency of the incoming Waves.

The auxiliary conductor 6 and the filament are connected through the battery 5. and .the Y oscillating vcircuit ll tuned to the frequency F. The device 8 is adapted to receive the currents at the secondary frequency F-F; consequently the control conductor 6, the plate 4: and the circuit connecting them form a generator of oscillations at the frequency F',

-which interfere vwith the incoming oscilla- Y tions at the frequency F so as to produce oscillations at the .secondary frequency F-F. The latteroscillations are then received in the Yreceiver 8 Which may be an amplifier, a telephone or the like. K A WhatIfclaim is:

Affreque'n'cy changer comprisingl a vacuum tube inside which are included a cathode emity.

ting electrons,zon one side of said cathode an anode and a grid between cathode and anode,

on the other vside a controlling electrode whose distance from the cathod is much smaller than that of the anode, a circuit receiving the Waves whose frequency F is to beV changed connected on one hand to the cathode and on the other to the grid, an oscillatory circuit Awhosernatural frequency F differs from F by the predetermined frequency f into which v the frequencyF must be changed, -said oscillatory circuit being connected on vone hand to the cathode and on theother hand simultaneously to the 'controlling electrode and to the negative pole of a battery Whose positive pole is connected to the anode', between said oscillatory circuit and the anode a receiving devicel adapted to Work at the frequency f=FF of the beats produced.

K In testimony whereof I havefaflixed my signature.

LUCIEN LEVY. 

